Enhancement of aerobic biodegradation process of organic waste

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 10 Issue: 09 | Sep 2023 www.irjet.net p-ISSN: 2395-0072
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 472
Enhancement of aerobic biodegradation process of organic waste
Shravan Zende1, Dinesh Gawatre2
1Student, Department of Civil Engineering, Sinhgad Academy of Engineering, Kondhwa, Maharashtra, India.
2Professor, Department of Civil Engineering, Sinhgad Academy of Engineering, Kondhwa, Maharashtra, India
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Abstract - The improvement of organic solid waste by
aerobic decomposition is the main topic of this paper,
particularly in the context of aerobic bioreactor landfills.
Traditional waste management practices such as open
burning, dumping, and landfills have several negative effects
on the environment and society. By increasingbiodegradation
under a regulated environment, bioreactorlandfillsprovidean
innovative solution. Tests, experiments, and methods used to
investigate the effectiveness of bioreactor landfills in the
decomposition of organic waste arepresentedin thisresearch.
Waste was collected from Katraj transfer station in Pune city.
An experimental setup was provided with an Aeration system
and soil layers in a bioreactor container. To speed up the
breakdown process, microorganisms including Phanerochaete
chrysosporium and Trichoderma were introduced. Results of
nutrients analysis of soil, physical characteristics of waste,
temperature, moisture content, settlement measurement,
leachate analysis, and BOD/COD ratio measurements. Are
included in this report. Experiments show that the presence of
microorganisms speeds up the decomposition process and
promotes the settling of the waste. Initially, the BOD/COD
ratio was higher indicating enhanced biodegradability.
BOD/COD ratio decreased gradually and remained constant
after 5 weeks resulting in 100% degradation of waste.
The Study concludes that aerobic bioreactor landfills
efficiently enhance the degradation of organicwaste. With the
introduction of microorganisms and proper management
strategies. Resulting in a faster landfill recovery period and
lowering environmental impact. Bioreactorlandfillsmayhave
higher startup expenses, but, it reduces long-term operating
and maintenance cost
Key Words:
C.O.D.- Chemical Oxygen Demand
B.O.D.- Biological Oxygen Demand
N.P.K.- Nitrogen Phosphorous Potassium
1.INTRODUCTION
The build-up of solid waste. is said to be at vital pointsin
practically every part of the earth. There are several
techniques used today to remediate solid waste. which
include composting, recycling, landfilling, and incineration.
The aerobic decomposition process, whichisoneofthemost
practical ways to recycle the organic part of solid waste, is
the main topic of this study. Because aerobic decomposition
produces less leachate and othertoxicgases,itisquickerand
less harmful to the environment. The increased energy
production from the breakdown of organic matter in the
presence of oxygen can be used to explain the quicker pace
of aerobic decomposition. Aerobic bacteria multiply more
quickly and carry out breakdown activities because of the
increased energy availability. Trichoderma and
Phanerochaete chrysosporium were the microorganisms
utilized in this experiment. There is a discussion of the
advantages of utilizing both microbes.
2. METHODOLOGY
3.1 Bioreactor Landfill
A bioreactor dump is a specific kind of landfill thatspeeds up
the biodegradation of garbage by using a controlled
atmosphere. Traditional landfills just drop garbageand wait
for it to break down, whereas bioreactor landfills utilize a
variety of approaches to mimic the conditions found in
nature to break down waste more quickly. Systems for
monitoring temperature,moisturecontent,andotherfactors
are in place at these landfills. In general, bioreactor landfills
are a potential method of waste management that can
increase the efficacy and efficiency of waste biodegradation
while also minimizing negative environmental effects and
generating renewable energy.
3.2 Experimentation
The project's analytical work must be carried out through
experimentation. Through this procedure, results may be
interpreted.
3.3 Need for Experimentation
1) The aerobic process is intricate. The entire process may
be understood by experimentation.
2) Experimentation will aid in determining the various
aspects of the aerobic response.
3) To comprehend or forecast the reaction, thefactorsmight
be associated.
3.4 Study area
The Katraj transfer station in Pune City will be where the
biodegradable solid trash is picked up. The city'sfastgrowth
in the production of solid waste, which causes

environmental damage, is one of its negative effects. Pune's
population, which is getting close to 34,000, is thought to
produce 1,200MT of solid trash per day.
Segregated waste is listed into the following categories:
 Flower
 Vegetable
 Leaves
 Fruit
 Household waste or leftover food.
3.5 Reactor Assembly
Fig. Setup
Fig. Reactor setup
1) Body of reactor-
20-liter plastic bottles were used to act as a bioreactor.
Bottles were cut from the top and a hole was drilled at the
bottom to make a collection system.Pipeswereconnected to
the hole and sealed by a multipurposesealant.Thevalvewas
fitted to the pipe for the controlled collection of leachates.
Plastic balls half cut and drilled with holes were stuck at the
bottom where leachate enters the pipe. This was done to
restrict the entry of large particles whichmayblock thepipe.
The apparatus was checked for leakages and assembled.
2) Aggregate layer-
A layer of aggregate was made to ensure the collection of
leachate equally. To act as a buffer zone between waste and
the base of the reactor. And to act as a coarse barrier
between waste and base.
3) Soil layer-
A layer of soil was added of approximately 2-3cm. Soil helps
to control the flow of leachate. It also acts as a natural filter.
And it acts as a fine barrier between the waste and the
underlying layer of coarse aggregates.
4) Aeration system-
Fish tank aerators were ordered and the pipe of the aerator
was drilled. This pipe was immersed in waste directly. This
ensured a constant supply of air at the rate of a 1.5-liter
minute.
5) Pre-treatment on waste-
Cutting organic waste is done in small pieces with a knife.
Due to this surface degradation increases and waste
degrades in less time.
3.6 Micro-organisms to be added to the waste sample.
Fungi and microorganisms were utilized with the
material. Macromolecular biological catalysts include
microorganisms. Microorganismsinteractwithsubstratesto
produce various compounds or products. Microorganisms
are required for nearly all cellular metabolic processes to
proceed at speeds quick enough to support life. To speed up
the pace of decomposition,microorganismswereintroduced
to the sample. The National Laboratories of India have a
variety of microorganisms. The selection of suitable
microorganisms proved challenging. The most effective
microorganismswerechosenafterstudyingseveral research
publications and considering the scientific statement.
These two microorganisms are available in the National
Chemical Laboratory of Pune. The order was placed online
on the site of NCL.

Thus, received micro-organisms were developed for their
culture and subculture. Micro-organisms to be added:
1. Phanerochaete chrysosporium
2. Trichoderma
These micro-organisms were received in agar form.
 Phanerochaete chrysosporium
A saprophytic fungus called Phanerochaete chrysosporium
may break down the woody portion of dead plants
organically. Therefore, P. chrysosporium thrives best on
plants that are already dead or are in the process of dying.
The loss of lignin from the plant structure can cause
symptoms like white spots of cellulose on the plant.
There is no known human or animal disease caused by this
fungus.
 Trichoderma
It serves to promote growth by acting as a biofertilizer.
Trichoderma can hasten the composting process. It
neutralizes both acidic and alkaline soils and brings pH
levels to the ideal range for nutrient availability to plants,
compost serves as a soil buffer.
3.7 Process of culture development.
1. Three hundred grams of peeled potatoes were cut
into small pieces.
2. These peeled potatoes were boiled in more than a
liter of water for 30 minutes.
3. The starch water formed was filtered by a clean
muslin cloth.
4. The final volume of 1 liter is made. 20g of Dextrose
and 0.1g of yeast extract is added.
5. This solution is then filled in test tubes which are
sealed with cotton.
6. These test tubes were sterilized.
7. 20g Agar was then placed with the help of a metaloop
in a sterilized atmosphere.
8. Test tubes were placed in a controlled atmosphere in
the incubator.
9. After a week, culture was formed.
3. RESULTS AND DISCUSSION
4.1 Nutrient analysis of soil (NPK)
Nutrient analysis of soil, aggregate, and organic waste was
carried out and nitrogen, phosphorus, and potassium
content were measured in the sample. The initial nutrient
content of analysis was in the range as it was effective in the
process of degradation of the organic matter. The nutrient
content of the samples is shown in Table 6.1. The result
showed that potassium content in soil was sufficient for the
degradation of waste.
Sr.
No.
Sample Nitrogen Phosphorus Potassium
1 Soil 247.5 kg/
ha (240-
480 kg/
ha)
142.5 kg / ha
(110-280 kg/
ha)
907.5kg/ha
(676.5-900
kg/ha)
Table 4.1 NPK value of soil
4.2 Initial stage analysis of organic waste
It included an analysis of the waste that was to be filled in
the reactor. The physical characterization of thewastegoing
in each reactor was checked and the percentage
characterization of the waste remains the sameasthatofthe
landfill site.
Physical characterization was done for every reactor and
readings were filled in the table shown below.
Flowers 3%
Leaves 4%
Husk 14%
Vegetables 54%
Miscellaneous 12%
Fruits 13%
Table 4.2 Composition of organic waste Component
Percentage by weight.
4.3 Analysis of moisture content and temperatureofthe
sample.
This analysis consisted of the physical observation
of the reactor. Physical observations were taken everyweek
to ensure that the moisture content and temperature are
within the required range.
Variation in the pH affects the process of
degradation rate. Initially, the pH of the reactor was as low
as 6.2. Initial pH was low in the first 10-15 days due to faster
degradation of organic matter and release of acid into the
leachate. During the acidic phase, waste showed a similar
trend throughout the process, with an average pH range of
6.5 to 7. Table 4.3 Moisture content, pH, and temperature of
sample:

Parameter observed
value
Recommended
value
References
Moisture
content
10.74 8.45 Pohland
(1986); Rees
(1980)
pH 6.2 6-7 Ehrig (1983)
Farquhar and
Rovers(1973)
Temperature 38° 45° Rees (1980)
Harts et
al.(1986)
Table 4.3 Moisture content, pH, and temperature of sample:
4.4 Analysis of Settlement and Leachate
This analysis consisted of daily taking
measurements of settlement and leachate collection. The
analysis of leachate was carried out daily to know the
reduction in variousparameterconcentrations.Thisanalysis
gave the variations that occurred as per the phases of the
degradations process in the reactors. The analysis of
leachate included different parameters such as pH, total
dissolved solids, chemical oxygen demand, and biochemical
oxygen demand for 3 days.
Parameter Value for aerobic
reactors
Value for open
dump
Total dissolved
solids
50.3 mg/l 102.4 mg/l
Table 4.4 Test of solids on leachate
In an aerobic landfill, oxygen is introduced to
support the aerobic degradation of organic waste, which
helps to reduce the production of leachate. As a result, the
TDS concentration in the leachate of an aerobic landfill is
generally lower compared to that of anaerobic landfills.
4.5 Settlement Observations
Week Aerobic
bioreactor +
Microbes
Aerobic
bioreactor
Open
Dump
1 6.3 5.2 5.3
2 10.7 9.5 9.1
3 15.6 14.1 13.2
4 20.1 17.2 15.8
4.5 20.9 19.9 18
Table 4.5: Settlement Observations, cm
A sudden increase in the settlement in the initial
stage was observed. This initial settlement was due to the
self-weight of the mass. The settlement is directly
proportional to the degradation rate of the organic matter.
As the degradation rate increases, the utilization of the
organic matter takes place which results in the settlement of
the resource in the reactor. The settlement reaches the
saturation value as the organic matter degrades completely.
A final settlement of 20.1 cm was observed in the reactor.
The rate of settlement in the reactor with the addition of
enzymes was more than in the reactor without microbes.
4.7 BOD/COD Ratio Observations
Week Aerobic
bioreactor +
Microbes
Aerobic
bioreactor
Open
Dump
1 0.8 0.75 0.65
2 0.63 0.69 0.8
3 0.45 0.51 0.59
4 0.31 0.39 0.41
5 0.1 0.23 0.27
6 0.1 0.112 0.198
7 0.1 0.1 1.006
Table 4.7: BOD/COD Ratio Observation
Graph of B.O.D / C.O.D. over time
Discussion on BOD/COD Ratio
BOD/COD ratio is necessary to determine the degradation
rate. When the degradation rate is more than the BOD/COD
ratio is also more. Initially, B.O.D. / C.O.D. is more because of
the high rate of degradation. Then, it seems to be slowing

down. It completely stops at the 20th week. Resulting in
100% decomposition.
4. CONCLUSIONS
 Degradation is a gradual process. But the addition of
micro-organisms speeds up the process. The rate of
settlement is more by 4.5 times in the reactor with
micro-organisms.
 The land gets recovered in much less time with just a
few measures such as leachate recirculation and the
addition of micro-organisms.
 The leachate recirculation ratio enhances the
biodegradability process, it also maintains the moisture
content required for thedegradationprocessandmicro-
organisms prove more effective when added with
leachate.
 Leachate acts as a nutrient to the micro-organisms.
 After the addition of micro-organisms, the BOD/COD
ratio increases,whichindicatesthatthebiodegradability
of organic waste is increased.
 The initial cost of this method is high but operational
and maintenance cost is low.
 Hence large-scale use of this project can improve the
degradation process and recover landfill sites in very
less time with a good cost/benefit ratio.
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